One of the important force is friction force between needle and cam In weft knitting Industry .In fact we can not decrease this force to zero. Because always cam trace has a friction coefficient that can not be ignored. But we can decrease the quantity of this force near zero. One of the methods in industry is lubrication of the cam trace which is based on cam angle. The other method which used in this project as a investigation method is making stitch cam that in the knock over point of it bearing is used. Because in the knock over point we can observe the most tension yarn and the maximum friction force which is caused by it .In this method, the cam path curve and the bearing location has been obtained. It is important to know that this relation between friction and tension of yarn increase a lot if other parameters don’t change. By making bearing cam, adjust that and doing necessary on it was indicated that using bearing in loop length and during using thin yarn cam help to reduce the yarn tension and decreasing of friction force. This reduction for a thin yarn and loop length can even reach to 7-8 cN which can help to increase the knitting machine efficiency.
